CBD Bioavailability: What’s the Best Way to Absorb CBD?

Editors note: I found a very interesting response video to this post two months after publishing it. I have embedded the video at the bottom of the post. Updated 10/9/18

Cannabis plants contain more than 60 chemical compounds, called cannabinoids. These molecules attach to specific receptors in the endocannabinoid system, most notably in the brain and the immune system. Cannabinoids are responsible for the effects of marijuana, such as feeling euphoric, relaxed, and even “high.” Tetrahydrocannabinol, or THC, is the psychoactive cannabinoid most widely studied.

However, ever since cannabidiol, or CBD, another cannabinoid, stopped five-year old Charlotte Figi from having seizures on CNN’s 2013 special Weed, demand is growing for this compound and scientists are studying it almost frantically. She even has a strain named after her, called Charlotte’s Web, which is low in THC and high in CBD. Millions of children are now using it worldwide to treat similar issues.

Unlike THC, CBD is non-psychoactive. It does not make its users “high.” In fact, according to the U.S. National Library of Medicine, several studies suggest that CBD effectively counteracts the psychological effects of THC, making it safe for children, pets, and anyone who does not enjoy the “high” associated with cannabis use. CBD itself is proving one of the most medically important compounds of all time.

Almost daily now, researchers are investigating new therapeutic uses for CBD. Scientists discovered the endocannabinoid system almost by accident, (Mechoulam et al, 1990), and its two primary receptors: Cannabinoid 1, or CB1, and cannabinoid 2, or CB2. CB1 receptors are abundant in the brain. When activated, they play a crucial role in motor control, memory processing, and pain perception.

THC binds to these CB1 receptors, which is why users feel “high” and lose all sense of pain. CBD, on the other hand, binds to CB2 receptors, which are active in the immune system. In this way, it is able to reduce inflammation, relieving pain at its source, and influence immune response to a myriad of medical conditions. It also regulates the immune system itself, which is vital for optimal health.

In 2012, the British Journal of Clinical Pharmacology published a review of many studies into the benefits of CBD. It found CBD possessing anticonvulsant, antiemetic, antipsychotic, anticancer, anti-inflammatory, antioxidant, and antidepressant properties. People use it to treat anxiety, pain, inflammation, seizures, nausea, cancer, infections, depression, PTSD, spasms and so much more.

Ways of Consuming CBD

For CBD to work, your body must first absorb it. This means that it must find its way from its point of entry and into the bloodstream, from where it can travel around the body to interact with cannabinoid receptors, such as CB2, as well as non-cannabinoid receptors, such as the vanilloid receptor TRPV-1 and the serotonin receptor 5-HT1A.

How it does this will depend on how you consume it, called the route of administration. The method of ingestion will greatly affect the uptake, distribution, and elimination of the CBD compound in your body. This is vitally important information, since the method you choose will determine how effective cannabinoid therapy will ultimately be in helping you overcome your medical issues.

You can consume CBD in a variety of different ways. You can swallow tinctures, add it to food, smear it on your skin, inhale it, and even swish it around your mouth. However, the way you choose to use it will influence the effect it has on you, as well as how long it takes to work. The body absorbs CBD in different ways, so how you consume it of paramount importance.

Absorption of CBD When Inhaled

You can smoke hemp flowers or other low-THC, high-CBD strains, such as Charlotte’s Web, or you can vape CBD concentrates, such as CBD oil, which have a greater CBD potency. Inhalation is an effective method of delivery and preferred by many because the body absorbs it quickly this way. Effects are near immediate, making it a good option for anyone needing pain relief now instead of hours later.

When you inhale CBD, such as vaping it, the alveoli in your lungs absorbs the compound very quickly. The lungs also offer a larger surface area for absorption. Once CBD passes through the alveoli, speedily since you are breathing continuously, it enters the bloodstream. From there, it travels quickly through the body. Compared to other methods, inhaling absorbs more CBD at once and much faster too.

Absorption of CBD When Ingested or Taken Sublingually

Without doubt, the most common method of administering CBD is orally, or via the mouth. It is quick, easy to dose, and convenient. When you take CBD this way, however, whether you eat it in food or swallow drops, it must first go through the digestive system. This process is lengthy. From the digestive tract, CBD then travels to the hepatic portal system, through the portal vein, and on into the liver.

In the liver, processes become a bit tricky. The U.S. National Library of Medicine published a study, (Ujvary and Hanus, 2016), detailing how the liver metabolizes CBD compounds. Called the “first pass effect”, CYP450 oxidases enzymes in the liver, which have mixed functions, break CBD down, reducing cannabidiol concentration significantly before sending the leftovers to the bloodstream.

Ingesting CBD, despite being the easiest method of delivery, is not particularly efficient at absorbing CBD in high concentrations and can take as long as two hours to work. However, another study (Huestis, 2009), also published by the U.S. National Library of Medicine, suggests that swallowing CBD with fatty acids may bypass this “first pass effect” and increase absorption rates of CBD after ingestion.

You can take CBD sublingually, which means holding it under the tongue for a minute or two before swallowing. This method allows the mucus membranes of the mouth to absorb CBD instead, bypassing the digestive system and metabolism in the liver entirely. Since no enzymes break the CBD molecules down and it does not travel through the stomach, CBD is able to reach the bloodstream faster.

Absorption of CBD When Applied Topically

When you smear CBD oils or creams onto your skin, it will never reach the bloodstream. In using CBD this way, you get targeted relief to a specific area. The skin absorbs CBD so that it can interact with cannabinoid receptors nearby. Generally, human skin is not very permeable. It blocks the majority of substances to prevent them from entering the body.

Your skin will not absorb cannabinoids very well. Absorption rates are very low. This is why, for topical CBD products to work, you have to apply them very generously, as in thick enough to break this barrier. If you are liberal enough in your application, your skin pores will absorb CBD to affect targeted healing. Additionally, this method works best when lotions, salves and balms contain very high levels of CBD.

The only topical CBD products able to penetrate the skin and enter the bloodstream are transdermal CBD patches. Transdermal, by its very definition, means able to cross the dermal barrier to reach the blood. The U.S. Library of Medicine discusses a study, (Hammell et al, 2016), proving the ability to CBD to be efficiently absorbed via transcutaneous methods.

There are other ways to consume CBD too, including rectally, via suppositories, and intravenously, injected into a vein. Both methods send CBD into the bloodstream very quickly, since absorption occurs via mucous membranes and directly respectively. However, almost nobody wants to inject CBD or insert suppositories. Although severely ill patients do use them, they are generally unpopular for most people.

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Update: Video Response

Here is a video from the Hurtin Hippie, a Canadian medical cannabis patient that produces medical marijuana (and related) videos.

I saw this video response a few months after this post was published, and would like to share it here, as the points he brings up are very relevant and important to consider in addition to the info presented in this article.

I asked that question of primary researcher/owner of Quality First International, Vinia Marquez, myself thinking MCT oil would be the best carrier because it’s saturated so skin-compatible, and thin enough to be absorbed, but she said unrefined coconut oil is a better solvent and it also absorbs better into the skin than either refined coconut or MCT oil, olive oil or ghee, the other four best. Research shows even oleic acid in olive and butter is an irritant and you don’t want to compromise the skin’s barrier function especially if one’s immune system is down. DMSO and plant oils are irritating except possibly Nerolidol/Geraniol, which are maybe a panacea from Devil’s Club and Geranium. Whip coconut oil infusion with a little water and lecithin. Coconut oil infusion takes a couple or three weeks 113F and lower. Looks for cold-pressed or Quality First’s pharmaceutically pure wet-milled, cold-extracted oil.